Process of making dialkyl barbituric acid.



UNlTEl) STATES fl? MAX ENGELA'IANN, OF ELBERFELD, GERM;

NY, ASSIGNOR TO FARBENFABRIKEN VORM.

FRIEDR. BAYER & (30., OF ,E LBlilltFELD, 'L'lERMANY, ACORPORATION OFGERMANY.

PROCESS OF MAKING DIALKYL BARBITURKG AGE).

Specification of Letters Patent.

Patented Feb. 18, 1908 Original application filed July 20 1906. SerialNo. 327-084. Divided and this application filed July 16. N07. Serial No.334,079.

To all whom it may concern:

Be it known that 1, MAX Excnmmxn, doctor of philosophy, chemist, citizenof the German Empire, residing at l llberfcld, Germany, Kingdom ofPrussia, have invented new and useful Improvements in Processes ofMaking Dialkyl Barbituric Acids, of which the following is aspecification.

My invention relates to a new process for the manufacture and productionof dialltyl barbituric acids (2.4.6trioxy-5-diall yl pyrimidins) beingas is known valuable soporilics.

This application, which is a divisional application from my applicationSerial No. 327,084, lilcd JulyZO, 1906, covers specifically the processfor the production of dialltyl barbituric acids in the presence ofcarbonic acid derivatives.

The new process consists in heating the dialliyl malonyl (liurethanes,l'iaving the formula:

n. rw'i-nn-coon If the thus obtained melt is extracted with boilingwater, the dialkyl barbituric acid can be separated from the impurities.However, in order to get the pure dialltyl barbituric acid, it isadvantageous to treat the melt for further purification with, dilutealkaline solutions. If dilute ammonia is used, then the ammoniacalliquid is filtered from unchanged diurethane, the filtrate boiled todrive off the ammonia, and allowed to cool. On cooling the (lialkylbarblturic acid is precipitated.

in order to carry out my process practically I can, for instance,proceed as follows, the parts being by weight:

Example 1. A mixture of 10 parts of diethyl malonyl diurethane with 7parts of urea is heated to 200 to 205 C. for 5 hours, and the melt isdissolved in an aqueous ammonia solution. and the filtrate is freed fromammonia by boiling it. The diethyl barbituric acid separates whilecooling. it can be further purified by recrystallizatioi'i from water.

Example 2. A mixture of 10 parts of dimethyl malonyl diurethane with 15parts of diphenyl carbonate (COJG H B) heated to 200 to .Bill (l. for 5hours, and. the'nielt is further treated as described in Example 1. l)imctl.iyl barbituric acid is thus obtained.

The process is carried out in an analo 'ous manner for the production ofothe .lia kyl barbituric acids, such as diprcpyl barbituric acid,methylethyl barbituric acid, or the like.

Having now described my invention and in what manner the same is to beperformed what I claim as new and desire-to secure by Letters Patent,is:

1. The process for the production of dial kyl barbituric acids havingthe above given general formula, which proces's consists in firstheating dialkyl malonyl diurethanes in the presence of carbonic acidderivatives and isolating from the thus obtained melt the resulting5-dialkyl-2.4.6trioxypyrimidins, substantially as described.

2. The process for the production of dialkyl barbituric acids, whichprocess consists in first heating dialkyl malonyl diurethanes in thepresence of carbonic acid deriva tives, dissolving the thus .obtainedmelt in ammonia, filtering the liquid, boiling the filtrate to drive offthe ammonia, and crystal lining the resulting5-dialkyl-2.4=.6-trioxypyrimidins therefrom, substantially as described.

3. The process for the production of diet-hyl barbituric acid, havingthe above given general formula, which process consists in first heatingdiethyl malenyl diurethanes in the presence of carbonic acidderivatives, and isolating from the thus obtained melt the resu ltin 5-di ethyl-2 i o-trioxypyrimidin, substantially as described.

4. The recess for the production of diethyl barbituric acid, whichprocess consists This solution is filtered,

- in'first heating diethyl malonyl diurethanes In testimony whereof Ihave hereunto set in the presence of carbonic acid derivamy hand in thepresence of two subscribing 10 tives, (lissogiing the obiairfdhmelt lilnwitnesses. ammonia, tering't e 'qui oi 'ng t e 5 filtrate, to drive ofithe ammonia, and crystal ENGELMANN' lizing the resulting5diethyl-2.4.6trioxy- Witnesses: pyrimidin therefrom, substantially asde- 1 OTTO KiiNIG, scribed. EWALD PBANTZ.

